The present invention relates to a optically writeable spatial light modulator of an liquid crystal type and relates to a driving method thereof, which may be utilized in an image processing device and an optical information processing device. More specially, the liquid crystal type composes a ferroelectric liquid crystal type having optical bistability.
Conventionally, the spatial light modulator of the ferroelectric liquid crystal type is utilized as an optical device for modulating an intensity of inputted image information on real time basis to output the modulated result. Generally, the outputted image is a binarized form of the inputted image. Further, the inventors have disclosed a method of driving the above noted optical modulator to produce an output image having a continuous gradation in Japanese Patent Application No. 239594/1990.
However, according to the conventional driving methods, there is produced only an output image associated to an intensity distribution of an input image. There could not be directly produced an output image in an edge enhanced form or an edge extracted form, which would be useful in optical information processing technology.